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# inputMetaParameterDefinition

A linear input value to plot on a curve.

```
var inputMetaParameterDefinition: PHASENumberMetaParameterDefinition { get }
```

## Discussion

This property defines the input value to plot on a graph defined by [`envelope`](/documentation/PHASE/PHASEMappedMetaParameterDefinition/envelope).

To retrieve the output value, an app passes the metaparameter’s [`value`](/documentation/PHASE/PHASEMetaParameter/value) to the [`evaluate(x:)`](/documentation/PHASE/PHASEEnvelope/evaluate(x:)) function.

---

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